Abstract and Introduction
Pelvic discontinuity is a challenging complication encountered during revision total hip arthroplasty. Pelvic discontinuity is defined as a separation of the ilium superiorly from the ischiopubic segment inferiorly and is typically a chronic condition in failed total hip arthroplasties in the setting of bone loss. After a history and a physical examination have been completed and infection has been ruled out, appropriate imaging must be obtained, including plain hip radiographs, oblique Judet radiographs, and often a CT scan. The main management options are a hemispheric acetabular component with posterior column plating, a cup-cage construct, pelvic distraction, and a custom triflange construct. The techniques have unique pros and cons, but the goals are to obtain stable and durable acetabular component fixation and a healed or unitized pelvis while minimizing complications.
Pelvic discontinuity, or separation of the ilium superiorly from the ischiopubic segment inferiorly, is a challenging complication encountered during revision total hip arthroplasty (THA) and occasionally during primary THA (Figure 1). In failed THAs, pelvic discontinuity is typically a chronic issue in the setting of bone loss. Most cases represent chronic nonunited stress fractures through severely deficient acetabular bone, but discontinuity may occur as a result of trauma, infection, or extensive acetabular reaming or impaction of press-fit acetabular components. Although the incidence of pelvic discontinuity in revision arthroplasty is likely underreported, most published series estimate it at 1% to 5%.[1–5] Reported risk factors include female sex, rheumatoid arthritis, and history of radiation therapy.[6,7] The keys to successful management of pelvic discontinuity include an accurate diagnosis followed by reconstruction that provides stable and durable acetabular component fixation and a healed or unitized pelvis while simultaneously minimizing complications.
Illustration of an AP view of the pelvis depicting a visible fracture line, obturator ring asymmetry, and medial migration of the inferior hemipelvis with disruption of the Köhler line on the left side, all of which are indicative of pelvic discontinuity. (Reproduced with permission from the Mayo Foundation for Medical Education and Research, Rochester, MN.)
Pelvic discontinuity can be categorized using a modification of the American Academy of Orthopaedic Surgeons (AAOS) acetabular bone deficiency classification[1,8] or by identification and further description of the bone loss using established classification systems, such as that of Paprosky et al. According to the AAOS classification, pelvic discontinuities are type IV deficiencies. Further subcategorizations include type IVa (ie, a pelvic discontinuity with a cavitary or mild segmental bone loss), type IVb (ie, a pelvic discontinuity with a large segmental or combined defect), and type IVc (ie, a pelvic discontinuity in a previously irradiated pelvis).
J Am Acad Orthop Surg. 2017;25(5):330-338. © 2017 American Academy of Orthopaedic Surgeons